Ok, well, short of that, this is one of the questions I get most and here's what I've noticed about venture raise timing. There seems to be three windows, each with their own pros, cons and complications.

Here are some general tips to keep in mind:

Phin tells companies to solve all the problems you can solve without money first. I think this is great advice.

The price of your deal matters less than who you get as an investor. If you get people who can actually help you succeed, whatever dilution you take now because of a lower price will pale in compare to what you don't have to take in later rounds because of your progress--and moreover what you will get after a better eventual outcome.

I'm a big believer in sharing what you're up to with investors early, even if you're not likely to get a deal. Their feedback about similar models and what you need to do go raise money will be invaluable.

So here's when I see people tend to raise:

Entrepreneur + Approach to a Market

Sometimes, the right person/team comes along and says "I want to tackle X market and I think this is how I'm going to do it." That's all they have--no demo no code--and they get funding. WTF? How's that even possible? You're slaving away learning to code and getting a prototype up and some fameball gets a check without even doing anything. How do I get that?

I'm not saying it's fair or a good idea, but here's what I see as the criteria:

You are the best team I could possibly conceive of approaching this market--either because of your industry experience, your prior track record, or because I already know you well and trust in your awesomeness.

I like the area that you're playing in.

This was the chloe + isabel bet. With 15 years in jewelry and paying her way through college selling CutCo knives, I couldn't think of anyone better than Chantel to start that business. Plus, I liked the economics and clear prospects for building a big company in that space.

You've launched or you're about to launch. I can login and kinda do most of the things you're going to let people do. There isn't any growth yet so all we have is a sneak peak at product direction and some confirmation that you have the ability to build something.

This is a confusing one for entrepreneurs--because some people get this round done but others don't. The issue is that you need an investor that has conviction--and very few have this. You need investor to say "I have a preconceived pattern in my head that this kind of product would work for this market, so I believe in it and I like what I'm seeing so far." The problem is that you have no idea which investors think what about particular products.

This was the Square bet. When Jack comes to you with that little reader, plugs it into his iPhone, and swipes you, you're in. Could Jack have raised money on is own without the demo? Probably. Sure. But that's not what he did. He built the demo first and if you were interested in mobile payments, he won you over. Traction? Before I joined First Round, I was the 476th and 477th dollar to be swiped on a Square--so there really was none--but I believed in the concept enough that I would have offered him a check.

This was also the GroupMe bet. I already believed in small, private groups going back to my observation of LiveJournal--where people's blogs were read by 5 people and mostly kept private. I didn't care so much about how many people were using it after 48 hours. It was a solution to a problem I already had in my head, plus I liked the guys.

There are other things at the same stage that I look at that I just don't feel the same about. I can't explain it so much, but I just don't believe in those models--and without any proof, it's really my opinion against yours... which brings us to...

I don't think your idea will fly. Who is going to do that? Wait? You have 250 paid customers already? Wait wait, I think maybe I'm a dumb VC who doesn't know everything and I need to take a look again.

When I first saw del.icio.us, I didn't get it. When I heard that 10,000 people had signed up, I was stunned that 10,000 people had figured out (in 2005) how to drag the tagging button up to the bookmarks bar. If enough people figured that out, there had to be something there.

If I don't believe in what you're doing, traction is what will prove me wrong. But it's got to be real traction--not a ton, but enough of the right traction to prove whatever hypothesis I have about it wrong.

What's real traction?

Returning users--people who make it part of their daily or weekly routine, and use it more and more.

People who need to do something not exactly easy to use it, like paying, contributing sensitive data, integration of some kind into their workflow, etc.

Traction on the tough part. You built a local merchant marketing tool, but can you sell it? Anyone can build that, but not everyone can sell it.

This was the SinglePlatform bet. I'd seen lots of ways local merchants could market themselves, but none with any kind of real traction. When I first saw the company, Wiley had strong growth in sales on a small base--like 100-150 merchants I think.. and they were paying. That's something.

I'd love for investors to weigh in here on whether they think this is accurate...